Two-Quantum 2D FT Electronic Spectroscopy of Biexcitons in GaAs Quantum Wells

Abstract

Seeing Double Whereas electrons roam free in a metal, their motion in a semiconductor often correlates with that of the positively charged holes their excitation has left behind. Various spectroscopic techniques have quantified the energetics associated with such electron-hole pairs, termed excitons. However, the higher-order correlations that ensue from exciton-exciton interactions are harder to probe. Now, Stone et al. (p. 1169 ) have characterized the dynamics of such exciton pairs, or biexcitons, directly in a gallium arsenide quantum well structure using a sequence of four ultrashort optical pulses with precisely controlled mutual phase relationships.